Mattie J.T. Stepanek was a poet, a peace activist, and the best-selling author of the Heartsongs poetry series. He was a motivational speaker and the National Goodwill Ambassador for the Muscular Dystrophy Association for three years. He died in June 2004 from dysautonomic mitochondrial myopathy. The Mattie Fund was established at MDA to specifically continue research of treatments and cures for childhood neuromuscular diseases.

Mattie's mom, Jeni Stepanek, is a Ph.D. candidate in early childhood special education. She is an inspirational speaker and writer and a national vice president for MDA. She lives in Maryland with Micah, the service dog she and Mattie shared.